Short-term exposure of high body weight heifers to testosterone-treated steers increases pregnancy rate during a late autumn-early winter natural service
Ungerfeld, R.
Anim. Reprod.;
6(3): 446-449, 2009. tab
Artigo
em Inglês
| VETINDEX
| ID: vti-9493
Resumo
Exposure to bulls seem to stimulate cyclic activity in postparitum beef cows, hasten puberty and increase pregnancy rate in heifers. The aim of this experiment was to determine if short-term exposure of pubertal beef heifers to testosterone-treated steers prior to late autumn-early winter bull breeding would increase pregnancy rates. An . Pregnancy was determined on Days 60 and 75. On Day 60, no differences were observed between groups in the frequency of pregnant heifers (18.2 vs 7.7% pregnant). On Day 75, more heifers in the biostimulation group that had an initial body weight ≥310 kg were pregnant (61.1 vs 32.4%, for stimulated and non-stimulated heifers respectively, P = 0.016), whereas there were no significant differences in heifers with lower initial body weight (17.9 vs 30.3% pregnant, for stimulated and non-stimulated heifers respectively). In conclusion, pregnancy rate was increased in high body weight heifers during late autumn-early winter natural service following pre-breeding exposure of the heifers to testosterone-treated steers.(AU)
Biblioteca responsável:
BR68.1
Localização: BR68.1
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